+1 to 'Technical' (Math, Decision Theory, Physics, etc)

+1 to promotion from all subreddits

+1 to Main as "Best of", or just getting rid of Main.

+1 to MIRI/FAI/Singularity stuff as a separate subreddit from EA stuff

Also, several historical posts have spanned multiple topics - some thought to a solution to this would be useful (this is the only reason that I might support keeping Main.)

The distinction between "Rationality theory" and "Rationality Practice" is what I think most people are getting at with Life improvement/Self-Improvement/Instrumental Rationality/Applied Rationality, regardless of the technical uses of those terms.

Another option is Links as a separate subreddit - the community norm here of prefacing with 'LINK:' is great, so an extension to a subreddit would be natural. Same goes for meetup announcements.